Editado por Reinhard Lieberei, Helmut Bianchi, Vera Boehm, Christoph Reisdorff

BRIENZA JUNIOR, S.

DENICH, M.

FOLSTER, H.

VLEK, P. L. G.

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EditorsLayoutPrintingReinhard Lieberei 1, Helmut K. Bianchi 2, Vera Boehm 1, Christoph Reisdorff 11 Universität Hamburg, Institut für Angewandte Botanik, Ohnhorststr. 18, 22609 Hamburg, Germany2 GKSS-Forschungszentrum Geesthacht GmbH,  Max-Planck-Straße 1, 21502 Geesthacht GermanyHelmut K. Bianchi, GKSS, Karsten Bittner, Documedia, Geesthacht, GermanyGKSS-Forschungszentrum Geesthacht GmbH, Geesthacht, GermanyISBN 3-00-010691-XLieberei, R., Bianchi, H-K., Boehm, V., Reisdorff, C., (eds.) 2002: Neotropical Ecosystems, Proceedings of the German-Brazilian Workshop, Hamburg 2000. GKSS-Geesthacht .The publishers give permission to copy single contributions from the Proceedings for personal use exclusively.Copies may be passed on only with the correct specification of the source.The research cooperation has been carried out under the auspices of the German - Brazilian GovemmentalAgreement on the Cooperation in Scientific Research and Technological Development.The issuance of the Proceedings and the production of the CD-ROM was sponsored (Code 0339991) by theThe responsibility for the contents of the contributions is solely the authors'.Federal Ministry of Education and Research German-Brazilian Workshop on Neotropical Ecosystems – Achievements and Prospects of Cooperative ResearchHamburg, September 3-8, 2000Posters, Session 5:  Recuperation of Degraded AreasBrienza, S. jun., Denich, M., Fölster, H. and Vlek, P.L.G.:Litterfall and Litter in Enriched Fallow with Fast Growing Trees in the Eastern Amazon of Brazil939AbstractLitterfall is the main process of transferring organic matterand nutrients accumulated in primary production, fromstanding aboveground tree biomass to the soil. Itsquantification can aid in understanding the nutrient andbiomass dynamics of an ecosystem. The present studyshows litterfall data estimated from enriched fallowvegetation with five leguminous trees (Acacia angustissimaKuntze, Clitoria racemosa G. Don, Inga edulis Mart.,Acacia mangium Willd. and Sclerolobium paniculatumVogel) in the Eastern Amazon of Brazil. A clear seasonalpattern of litterfall was observed during the period studied.For all species, the greatest intensity of litterfall wasregistered during the period of lowest precipitation. Thegreatest fall intensity occurs at the spacing of 1 m x 1 m,followed by 2 m x 1 m, 2 m x 2 m and the control, and theannual accumulated litterfall biomass was dependent ofspecies and spacement.KeywordsFallow vegetation, Leguminous trees, Amazon region,Fallow enrichment, Litterfall.1 IntroductionIn a forest ecosystem, the returns of organic matter andnutrients from vegetation to the soil can occur in thefollowing manner: i) litterfall (leaves, branches and logs);ii) decomposition and root nutrient exudation; and iii) rainwash from standing vegetation (NYE, 1961). Litterfall is themain process of transferring organic matter and nutrientsaccumulated in primary production, from standing above-ground tree biomass to the soil (VITOUSEK, 1984; SZOTT etal., 1991). Therefore, its quantification can aid in under-standing the nutrient and biomass dynamics of an ecosy-stem. In the present study, the litterfall was estimated inenriched fallow vegetation in the Eastern Amazon of Brazil. 2 Material and MethodsThe enrichment of fallow biomass, conserving the fallowvegetation as a base for biodiversity and keeping the shortfallow time, was studied in the Eastern Amazon of Brazilianbased on a traditional slash-and-burn system of maize (cul-tivar BR 106, planted in January 1995 at 1.0 m x 0.5 m;SOUZA et al., 1999) and cassava (cultivar "olho verde”, plan-ted in February 1995 at 1 m x 1 m). Using experimentalplots of 10 m x 8 m in four randomized blocks, theleguminous trees Acacia angustissima Kuntze, Clitoriaracemosa G. Don, Inga edulis Mart. and Acacia mangiumWilld. were planted after maize harvest (June 1995) and fourmonths after cassava had been planted (February 1995) atspacing of 1 m x 1 m, 2 m x 1 m and 2 m x 2 m. Trees andcassava grew together for eight months until the cassava beharvested (February 1996). After the last cassava weeding(between October-November 1996) the fallow vegetationstarted to grow as an enriched fallow. The litterfall werestudied from April 1996 to April 1997 considering plantedtrees and natural fallow. Biomass of leaves, branches,flowers and fruits collected inside the boxes (50 cm x 50cm) placed 10 cm of above the soil surface, was consideredlitterfall.3 Results/Discussion/ConclusionsA clear seasonal pattern of litterfall was observed during theperiod studied. For all species, the greatest intensity oflitterfall was registered during the period of lowestprecipitation (from September to December) and the lowestvalues coincided with the rainy period (from January toAugust). Under the conditions of the present study, thefollowing phenological characteristics of trees planted forfallow vegetation enrichment were observed during theperiod of low precipitation:a) Acacia angustissima: among the species studied, it is theone that possesses the smallest leaflet size. From thebeginning to the end of the period of low rainfall, thisspecies exhibited a gradually of decreasing litterfall untilthe complete absence of leaves. Its branches were visible atthe end of the dry season. At the first rain, its leaves quick-ly started to re-growth. This species was in its floweringLitterfall and Litter in Enriched Fallow with Fast Growing Trees in the Eastern Amazon of BrazilBrienza, S. jun.1, Denich, M.2, Fölster, H.3 and Vlek, P.L.G.21Embrapa – Amazônia Oriental, Belém, Brazil2Universität Bonn, Bonn, Deutschland3George-August Universität Göttingen, DeutschlandGerman-Brazilian Workshop on Neotropical Ecosystems – Achievements and Prospects of Cooperative ResearchHamburg, September 3-8, 2000Posters, Session 5:  Recuperation of Degraded AreasBrienza, S. jun., Denich, M., Fölster, H. and Vlek, P.L.G.:Litterfall and Litter in Enriched Fallow with Fast Growing Trees in the Eastern Amazon of Brazil940process at 12 months of age (July-96) and fructificationended in December-96;b) Clitoria racemosa: under isolated conditions it shows alarge canopy. However, in the present study this species didnot develop a dense canopy, even with the spacing of 2 m x2 m, where theoretically it would better be able to expressits natural form. This species also gradually lost all its lea-ves during the driest period. Fast new leave developmentwas observed after the first rainfall;c) Inga edulis: this species has large leaves. Its canopy isgenerally ramified and broad under natural conditions. Inthe experiment, planting in open spaces and in lines with inthe fallow vegetation stimulated its apical development.This species also lost its leaves gradually until its completeabsence during the driest period.  Fast leave growths occur-red after the first rainfall; andd) Acacia mangium: this species has a typical forest formand strong apical dominance. Unlike the other speciesstudied, it did not completely lose its leaves during the dryperiod. Its canopy always remained green.Thus, besides precipitation, litterfall also reflected differentphysiological characteristics of the species studied(deciduous or semi-deciduous species).The greatest fall intensity occurs at the spacing of 1 m x 1m, followed by 2 m x 1 m, 2 m x 2 m and the control, andthe annual accumulated litterfall biomass was dependent ofspecies and spacement (Fig. 1). The largest litteraccumulation provided by I. edulis (5037 kg ha-1) planted atthe spacing 1 m x 1 m was 2.3 times larger than the control(2190 kg ha-1), whereas the lowest (C. racemosa planted at2 m x 1 m) production was only 1.2 times more than thecontrol.Planting a larger number of trees per hectare implied alarger accumulated biomass of litter. But the litter biomassratio between planted leguminous trees and the associatedfallow vegetation varied between species and plantingdensity (Tab. 1). Litter biomass of the planted treespredominated except for C. racemosa (45%). The species I.edulis and A. mangium were the greatest litter biomasscontributors (74%). The litter biomass ratio between plantedleguminous trees and the associated fallow vegetationvaried from 3:1 for systems with A. angustissima, I. edulisand A. mangium, and 1:1 for C. racemosa. Considering onlythe average values of each spacing studied, regardless ofleguminous trees, the result showed that as the number oftrees planted per hectare decreased, the litter biomass ofplanted trees and fallow vegetation became similar. Thebiomass rates of planted trees and fallow vegetation was4.6-to-1, 2.3-to-1 and 1-to-1 respectively at the densities of1 m x 1 m, 2 m x 1 m and 2 m x 2 m (Tab. 1).The observation that at a planting density of 2 m x 2 m(2500 trees ha-1), practically 50% of produced biomasscame from planted trees, is important information in thesearch for enrichment systems that minimize possible nega-tive impacts on fallow vegetation biodiversity.Fig. 1: Annual accumulated litterfall and standard errors of control and leguminoustrees A. angustissima, C. racemosa, I. edulis and A. mangium planted at the spacing1m x 1m, 2m x 1m and 2m x 2m (n=4)German-Brazilian Workshop on Neotropical Ecosystems – Achievements and Prospects of Cooperative ResearchHamburg, September 3-8, 2000Posters, Session 5:  Recuperation of Degraded AreasBrienza, S. jun., Denich, M., Fölster, H. and Vlek, P.L.G.:Litterfall and Litter in Enriched Fallow with Fast Growing Trees in the Eastern Amazon of Brazil9414 ReferencesSOUZA, F.R.S. DE; VELOSO, C.A.C.; POLTRONIERI, L.S.;ARAÚJO, S.M.B. DE. 1999: Recomendações básicas para o cultivo demilho no Estado do Pará. Belém: Embrapa Amazônia Oriental, 20 p.(Embrapa Amazônia Oriental. Circular Técnica, 2).Tab. 1: Percentage of total accumulated litterfall biomass (kg ha-1) fractionated in fallow vegetation; planted trees (A. angu-stissima, C. racemosa, I. edulis and A. mangium; spacing of 1 m x 1 m, 2 m x 1 m and 2 m x 2 m) and others (flowers, fruits,seeds and branches) (SE = standard error and CV = coefficient of variation). Data followed by the same letter and located inthe same group (natural fallow and legume) are not statistically different (p<0.0001)

Litterfall and litter in enriched fallow with fast growing trees in the eastern Amazon of Brazil.

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Litterfall and litter in enriched fallow with fast growing trees in the eastern Amazon of Brazil.

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